func (st *State) constraintsValidator() (constraints.Validator, error) {
// Default behaviour is to simply use a standard validator with
// no environment specific behaviour built in.
defaultValidator := constraints.NewValidator()
if st.policy == nil {
return defaultValidator, nil
}
cfg, err := st.EnvironConfig()
if err != nil {
return nil, err
}
validator, err := st.policy.ConstraintsValidator(cfg)
if errors.IsNotImplemented(err) {
return defaultValidator, nil
} else if err != nil {
return nil, err
}
if validator == nil {
return nil, fmt.Errorf("policy returned nil constraints validator without an error")
}
return validator, nil
}
// ConstraintsValidator is defined on the Environs interface.
func (e *environ) ConstraintsValidator() (constraints.Validator, error) {
validator := constraints.NewValidator()
validator.RegisterUnsupported([]string{constraints.CpuPower})
validator.RegisterConflicts([]string{constraints.InstanceType}, []string{constraints.Mem})
return validator, nil
}